Valve, actuator and control system therefor

ABSTRACT

A valve, actuator and control system that allows minimizing the size of the actuator and operation of the control system in a manual mode that automatically prevents accidental operation by pipeline pressure is disclosed. The actuator uses gas pressure from the pipeline to power the actuator. In the event gas pressure is unavailable, a pair of manual hand pumps are incorporated to allow operation of the actuator and valve.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a system of a hydraulic actuator for operatinga valve between open and closed positions and the control system used toregulate the operation of the actuator. This system is particularlysuited for operation of ball valves used in the oil and gas industry.These ball valves are typically used in gas pipelines to control theflow of gas through the pipeline. The actuator of the present inventionuses gas pressure from the pipeline to power the actuator. In the eventgas pressure from the pipeline is unavailable or inaccessible, a pair ofmanual hand pumps are incorporated to allow operation of the actuatorand valve.

Prior actuators utilizing the gas pressure of the pipeline as a powersource typically have a double acting piston upon which the gas acts todrive the actuator and hence the valve to be opened or closed. Theseactuators have vented the gas pressure from one side of the doubleacting piston as gas pressure is applied to the other side of thepiston. This venting is necessary to ensure that equal pressure is notacting on both sides of the piston simultaneously. In this event, theforce acting on both sides of the piston would balance and the actuatorwould fail to operate or be “pressure locked” as commonly referred to inthe industry.

As a result of the need to vent each side of the actuator piston toensure proper operation, the gas pressure is usually vented toatmosphere. This gas is not a pure gas but in fact has hydrocarbonliquids entrained in the gas, known as condensate in the industry. Whenthis venting to atmosphere occurs, the hydrocarbon liquid condensatecondenses and becomes a sticky, unsightly oily residue on the groundadjacent the valve and actuator. In recent years this venting to theatmosphere of the gas has raised environmental concerns due to possiblecontamination of the ground and groundwater by this oily residue.

Another concern with prior valve, actuator and control system assemblieshas been the interface and operation of the manual hand pumps that arerequired to operate the actuator and valve when gas pressure from thepipeline is not available. This may occur during new installations whenthe pipeline has not been filled with gas yet and opening or closing ofthe valve is needed. Other times when maintenance is to be performed onthe valve or actuator, the pipeline must be bled of gas pressure as asafety precaution. When it is desired to operate the valve prior tosubsequent pressurization of the pipeline, the ability to operate thevalve and actuator manually is required. Prior valve, actuator andcontrol system assemblies have had problems in their design andoperation that allowed possible scenarios in which pressurization of thepipeline and thus the actuator, could result in inadvertent operation ofthe actuator while manual operation of the actuator was occurring andpossible injury to an operator. It is therefore desirable to have avalve, actuator and control system assembly that allows minimizing thesize of the actuator and operation of the control system in a manualmode that automatically prevents accidental operation by pipelinepressure. The valve, actuator and control system of the presentinvention offers such novel features.

2. Description of Related Art

U.S. Pat. No. 6,231,027 B1 to G. S. Baker et al. shows a valve actuatorthat utilizes a variable helix angle to generate greater operatingtorque near the end of its travel.

A subsea rotary adjusting device for valves is disclosed in PCTInternational Publication No. WO 02/37008 A1 to K. Biester et al. Thedevice utilizes a helical slot in a sleeve to translate axial motioninto rotary motion.

PCT International Publication No. WO 03/025428 A1 to K. Biester et al.shows a travel multiplying device utilizing three concentric pipes withspherical linking elements to magnify relative longitudinal motionbetween adjacent pipes.

SUMMARY OF THE INVENTION

The present invention relates to a system of a hydraulic actuator foroperating a valve between open and closed positions, the valve itselfand the control system used to regulate the operation of the actuator.The valve is installed in a gas pipeline, typically used in the oil andgas industry, to control flow through the pipeline. The actuator of thepresent invention uses gas pressure from the pipeline to power theactuator.

The valve is a ball valve that uses a spherically shaped ball to controlfluid flow through the valve. End flanges are welded to the outer bodyshell for connection to mating pipeline connections. A quarter turn ofthe ball moves the valve from open to closed positions. The valveactuator is mounted on top of the valve and rotates the ball betweenopen and closed positions when operated.

The valve actuator is comprised of a lower actuator housing with a boretherethrough to which an actuator cylinder housing having a counterboreis secured in sealing engagement to a first end of the lower actuatorhousing. A lower actuator plate with a bore is secured to the second endof the lower actuator housing. A helix sleeve is secured within thelower actuator housing bore and seals therein. The helix sleeve has apair of helical slots cut in its wall and a reduced diameter bore on oneend. An actuator drive shaft extends between the actuator cylinderhousing bore and the reduced diameter bore of the helix sleeve and sealswithin these bores and is axially restrained between them.

An actuator piston sleeve is sealingly disposed in the annulus betweenthe actuator drive shaft and the actuator cylinder housing with theactuator piston sleeve axially moveable in response to hydraulicpressure. The actuator piston sleeve has a reduced diameter portionextending into the annulus between the actuator drive shaft and thehelix sleeve with the reduced diameter portion of the actuator pistonsleeve sealing on the actuator drive shaft and the reduced diameterportion of the actuator piston sleeve having a pair of axially disposedslots. A pair of rollers are attached to the reduced diameter portion ofthe actuator piston sleeve and engage the helical slots in the helixsleeve and a second pair of rollers are attached to the actuator driveshaft and engage the axially disposed slots in the reduced diameterportion of the actuator piston sleeve such that reciprocation of theactuator piston sleeve causes rotation of the actuator drive shaft.

The hydraulic control system for the valve actuator is comprised of openand close circuits with each circuit including a control valve, a pairof pilot operated valves and a fluid supply tank for supplying controlfluid under pressure to the appropriate actuator function. The outletport of the second pilot operated valve in each circuit is connected toan exhaust orifice valve. The control valve in each circuit receivespressurized gas from an outlet on the pipeline and directs thispressurized gas to the appropriate tank when the control valve isoperated. This pressurized gas is also used to operate the pilotoperated valves to control venting of pressure from one tank while theother is being pressurized to prevent pressure lock and allowequalization of pressure between the tanks after the valve is moved toits fully open or closed position.

A principal object of the present invention is to provide a valve,actuator and control system that allows minimizing the size of theactuator and operation of the control system in a manual mode thatautomatically prevents accidental operation by pipeline pressure.

Another object of the present invention is to provide a valve, actuatorand control system that is modular in construction to allow adaptationto different valve sizes.

A final object of the present invention is to provide a valve, actuatorand control system for gas pipelines that minimizes the condensatevented to the atmosphere during operation.

These with other objects and advantages of the present invention arepointed out with specificness in the claims annexed hereto and form apart of this disclosure. A full and complete understanding of theinvention may be had by reference to the accompanying drawings anddescription of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the present invention are setforth below and further made clear by reference to the drawings,wherein:

FIG. 1 comprises a perspective view of a system for controlling fluidflow through a pipeline including valve, actuator and control systemassembled together. FIG. 2 is a perspective view from the opposite sidewith partial sectional views of valve 12 and actuator 14 to show themain components sectional view of a wellhead system with the right halfof the view showing a combination of standard casing hangers and packoffassemblies and the left half of the view showing a combination of casinghangers and packoff assemblies for emergency situations in which thecasing sticks in the well bore while being lowered into position.

FIG. 2 comprises a perspective view from the opposite side with partialsectional views of the valve and actuator to show the main components.

FIG. 3 comprises a sectional view of the valve actuator in the valveclosed position.

FIG. 4 comprises a sectional view of the valve actuator in the valveopen position.

FIG. 5 comprises a perspective view of the actuator and actuation of thehelix sleeve therein.

FIG. 6 comprises a schematic view of the control system.

FIG. 7 comprises a view of the flow diagram of the control system.

FIG. 8 comprises a sectional view of the fluid supply tanks and manuallyoperated valves mounted thereon of the control system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings, and particularly to FIG. 1 a perspectiveview of a system 10 for controlling fluid flow through a pipelineincluding valve 12, actuator 14 and control system 16 assembled togetheris shown. FIG. 2 is a perspective view from the opposite side withpartial sectional views of valve 12 and actuator 14 to show the maincomponents. Valve 12 is a ball valve of the type commonly used in theoil and gas industry, with a welded body 18 and end flanges 20 forinstalling valve 12 into a pipeline (not shown) through which valve 12will control the flow of oil and gas. Valve 12 includes a flowcontrolling member or ball 22, disposed in welded body 18, with a bore24 therethrough. Seal elements 26 in welded body 18 seal against ball22. Rotation of ball 22 a quarter turn by actuator 14 closes valve 12.

Actuator 14 includes lower actuator housing 28 to which actuatorcylinder housing 30 is secured. Helix sleeve 32 is disposed within loweractuator housing 28 and actuator piston sleeve 34 is positioned withinhelix sleeve 32. Details of construction of actuator 14 and actuation ofhelix sleeve 32 are shown in sectional views FIGS. 3 and 4 andperspective view FIG. 5. FIG. 3 shows actuator 14 in the position ofvalve 12 being closed and FIG. 4 shows actuator 14 in the position ofvalve 12 being open. Lower actuator housing 28 has bore 36 extendingtherethrough. Actuator cylinder housing 30 has counter bore 38 extendingtherein and is secured to lower actuator housing 28 by suitable securingmeans as studs 40 and nuts 42. Bore 36 and counterbore 38 are axiallycoincident. Lower actuator housing 28 is sealed against actuatorcylinder housing 30 by sealing means in the form of seal ring 44.

Lower actuator plate 46 and guide sleeve 48 are secured to the oppositeend of lower actuator housing 28 by suitable securing means as studs 50and nuts 52. Lower actuator plate 46 and guide sleeve 48 have bores 54and 56 therethrough. Helix sleeve 32 is secured within lower actuatorhousing 28 by lower actuator plate 46 and actuator cylinder housing 30.Seal ring 58 seals helix sleeve 32 to lower actuator housing 28 whilefirst and second securing means in the form of anti-rotation or dowelpins 60 and 62 between helix sleeve 32 and lower actuator housing 28prevent helix sleeve 32 from rotational movement with respect to loweractuator housing 28 and actuator cylinder housing 30.

Helix sleeve 32 includes reduced diameter bore 64 on the end adjacentlower actuator plate 46. Actuator drive shaft 66 is a cylindrical memberthat extends between bore 68 in actuator cylinder housing 30 and reduceddiameter bore 64 of helix sleeve 32. Actuator drive shaft 66 is sealedin bores 64 and 68 by seal rings 70 and 72, respectively. Bore 68 isaxially coincident with counter bore 38 as is stepped bore 74 inactuator cylinder housing 30. Adjacent reduced diameter bore 64 isstepped bore 76 in helix sleeve 32. Stepped bores 74 and 76 act toaxially restrain actuator drive shaft 66 when actuator 12 is assembled.

Actuator piston sleeve 34 is sealingly disposed in the annulus betweenactuator drive shaft 66 and counter bore 38 of actuator cylinder housing30. Seal rings 80 and 82 seal actuator piston sleeve 34 to actuatordrive shaft 66 and counter bore 38 of actuator cylinder housing 30.Actuator piston sleeve 34 has a reduced diameter portion 84 that extendsinto the annulus between actuator drive shaft 66 and helix sleeve 32 andseals on actuator drive shaft 66 with seal ring 86. Reduced diameterportion 84 of actuator piston sleeve 34 has a pair of axially disposedslots 88 formed therein. An actuation means in the form of a pair ofrollers 90 are secured to actuator drive shaft 66 at approximately itsmiddle and rollers 90 engage axially disposed slots 88 for purposes tobe described hereinafter. Helix sleeve 32 includes a pair of helicalslots 92 formed in its wall. As best seen in FIG. 5, a second actuationmeans in the form of a pair of rollers 94 are secured to the lower endof reduced diameter portion 84 of actuator piston sleeve 34 at rightangle to axially disposed slots 88 and engage helical slots 92 in helixsleeve 32.

First end 96 of actuator drive shaft 66 extends beyond stepped bore 74and includes indicator means or slot 98 formed thereon to indicate therotational position of actuator drive shaft 66. Opposite or second end100 of actuator drive shaft 66 extends beyond stepped bore 76 andincludes engaging means in the form of male spline 102 formed thereon.Valve closure adapter 104 engages spline 102 and connects to valve 12with spline 106 to transmit the torque generated by actuator 14. Ports108 and 110 in actuator cylinder housing 30 allow pressurized hydraulicfluid, supplied by control system 16 in a manner to be describedhereinafter, to operate actuator 12 in the following manner.

As noted above, FIG. 3 shows actuator 14 in the position with valve 12closed. Actuator piston sleeve 34 is at the bottom of its stroke. Whenit is desired to open valve 12, pressurized hydraulic fluid to suppliedto port 108 while port 110 is vented. The pressurized hydraulic fluidacts on the underside of actuator piston sleeve 34 against the annularpiston area defined by seals 80 and 82 while seals 44, 58 and 70maintain pressure in lower actuator housing 28. As actuator pistonsleeve 34 is urged upwardly, slots 88 move axially over rollers 90 onactuator drive shaft 66. Simultaneously, rollers 94 on reduced diameterportion 84 of actuator piston sleeve 34 are engaging helical slots 92 ofhelix sleeve 32. As helix sleeve 32 is anti-rotated with respect tolower actuator housing 28 by pins 60 and 62, rollers 94 are forced tomove along helical slots 92 of helix sleeve 32 which causes actuatorpiston sleeve 34 to rotate with respect lower actuator housing 28. Thisrotation of lower actuator housing 28 is transmitted through axial slots88 and rollers 90 to actuator drive shaft 66, thus rotating valveclosure adapter 104 and valve 12 through splines 106 to move valve 12 toits open position shown in FIG. 4. When it is desired to close valve 12,pressurized hydraulic fluid is supplied to port 110 while port 108 isvented to reverse the direction of rotation.

Operation of valve 12 and actuator 14 is regulated by control system 16which is shown in schematic form in FIG. 6 and in flow diagram form inFIG. 7. FIG. 6 shows control system 16 includes first and second controlvalves 200 and 202 controlling operation of actuator 14 through firstthrough fourth pilot operated valves 204, 206, 208 and 210. Valves200-210 control hydraulic fluid flow from first and second actuatorfluid supply tanks 212 and 214 to the open and close ports 108 and 110of actuator 14. Control system 16 includes a fluid pressure source 216which is gas pressure supplied from the pipeline (not shown) throughwhich valve 12 and actuator 14 control gas flow. Control system 16further includes a normally open double pilot operated two way valve 218to equalize gas pressure between tanks 212 and 214 which is bled toatmosphere through exhaust orifice valve 220. First and second actuatorfluid supply tanks 212 and 214 have hydraulic fluid 222 in their lowerportion which is the pressurized fluid supplied to actuator 14.Hydraulic fluid 222 is pressurized by the action of pipeline gaspressure acting thereon.

The flow diagram of FIG. 7 shows details of the construction of thecomponents of control system 16 and the gas and hydraulic fluid flowtherebetween. Control system 16 is divided into first and second controlcircuits 224 and 226. First control circuit 224 acts to supply hydraulicfluid 222 to port 108 and operate actuator 14 to close valve 12, whilesecond control circuit 226 acts in reverse to supply hydraulic fluid 222to port 110 and operate actuator 14 to open valve 12. Additionally,control system 16 includes manually operated hand pumps 228 and 230mounted on first and second actuator fluid supply tanks 212 and 214,respectively, for purposes to be described hereinafter.

First and second control valves 200 and 202 are manually operated valvesincluding inlet port 232, outlet port 234 and vent port 236. In theclosed position, fluid flow between inlet port 232 and outlet port 234is blocked while outlet port 234 is connected to vent port 236. In theopen or operating position, fluid flows between inlet port 232 andoutlet port 234 while vent port 236 is blocked. First through fourthpilot operated valves 204, 206, 208 and 210 are two way normally closedpilot operated valves including inlet port 238, outlet port 240 andpilot port 242. In the closed position, i.e., no pressure supplied topilot port 242, fluid flow between inlet port 238 and outlet port 240 isblocked. In the open, i.e., pilot operated position, pilot pressuresupplied to pilot port 242 allows fluid flow between inlet port 238 andoutlet port 240. First and second control valves 200 and 202 and firstthrough fourth pilot operated valves 204, 206, 208 and 210 are mountedin a manifold block (not shown) in a manner well known to those ofordinary skill in the art Control system 16 also includes double pilotoperated two way valve 218 with pilot pressures supplied from first andsecond control circuits 224 and 226.

First and second actuator fluid supply tanks 212 and 214 are identicalin construction. Tanks 212 and 214 are supplied with hydraulic fluid 222partially filling the tanks. Baffles 246 are positioned in tanks 212 and214 to aid in maintaining separation between the pressurized gassupplied by the pipeline and hydraulic fluid 222. Manually operated handpumps 228 and 230 and mounted on tanks 212 and 214, respectively, andeach pump 228 and 230 includes shuttle valve 252 mounted thereon.

Details of construction and operation of tanks 212 and 214, pumps 228and 230 and shuttle valves 252 are shown in FIG. 8. Only the descriptionof tank 212, pump 228 and shuttle valve 252 are given as tank 214 andpump 230 are identical thereto. Pump 228 is mounted to tank 212 bydouble flange 254 with pump 248 extending into tank 212 and immersed inhydraulic fluid 222. Pump 228 is of the “sucker rod” type well known tothose of ordinary skill in the art with hydraulic fluid 222 being drawninto pump 228 through spring loaded ball 256 when handle 258 is strokedaway from tank 212. Hydraulic fluid 222 is pressurized in pump 228 ashandle 258 is stroked toward tank 212 and unseats spring loaded ball 260and is directed out port 262 to shuttle valve 252. Shuttle valve 252shuttles between a position in which fluid from port 262 flows throughshuttle valve 252 to outlet port 264 and to either port 108 or 110,depending on which tank is being used, and a second position in whichpressurized hydraulic fluid 222 is received into port 266 and to outletport 264. Pressurized hydraulic fluid 222 is supplied to port 266through a by pass passage 268 in double flange 254. Pressurizedhydraulic fluid 222 is only supplied to by pass passage 268 when tank212 is pressurized by gas supplied through first and second controlcircuits 224 and 226.

A typical sequence of operation for control system 16 would be asfollows assuming valve 12 is in the open position and it is desired toclose valve 12. Referring to the flow diagram of FIG. 7, first controlcircuit 224, i.e., the “close” circuit, is operated by depressing firstcontrol valve 200. This operation causes the following functions tohappen as pressurized gas is supplied:

-   -   (i) directs pressurized gas pressure to pilot operated normally        open valve 218 to equalize pressure between actuator open fluid        supply tank 214 and actuator close fluid supply tank 212;    -   (ii) directs pressurized gas pressure from outlet port 234 of        first control circuit control valve 200 to pilot port 242 of        first pilot operated valve 204 of valve closing first control        circuit 224 to operate first pilot operated valve 204 and allow        pressurized gas pressure to pressurize hydraulic fluid 222 in        actuator close fluid supply tank 212 and supply pressurized        hydraulic fluid 222 through by pass passage 268, through port        266 to outlet port 264 and thence to port 108 (close port) of        actuator 14 to close valve 12; and,    -   (iii) directs pressurized gas pressure from outlet port 240 of        first pilot operated valve 204 of first control circuit 224 to        pilot port 242 of fourth pilot operated valve 210 of valve        opening second control circuit 226 to operate fourth pilot        operated valve 210 and vent pressurized gas pressure from        actuator open fluid supply tank 214 through exhaust orifice        valve 220. Closure of first control circuit control valve 200 to        a closed position and operation of second control circuit        control valve 202 to an open position results in the same        operations described above but in reverse order to open valve        12.

If pressurized gas pressure is not available as in the case of a breakin the pipeline and it is necessary to close valve 12, manually operatedhand pump 228 on actuator close fluid supply tank 212 may be operated.Such operation pressurizes hydraulic fluid 222 in tank 212 as describedabove and directs such fluid 222 through port 262 to port 108 ofactuator 14 to close valve 12. Note that such operation causes shufflevalve 252 to shift and block port 264 and automatically lock out gaspowered control circuit 224, if any residual pressure is present. Shouldopening of valve 12 be desired, pump 230 in actuator open fluid supplytank 214 may be operated to reverse operation and open valve 12.

The construction of our system for controlling fluid flow through apipeline including valve, actuator and control system will be readilyunderstood from the foregoing description and it will be seen that wehave provided a system that allows minimizing the size of the actuatorand operation of the control system in a manual mode that automaticallyprevents accidental operation by pipeline pressure while minimizing thecondensate vented to the atmosphere during operation. Furthermore, whilethe invention has been shown and described with respect to certainpreferred embodiments, it is obvious that equivalent alterations andmodifications will occur to others skilled in the art upon the readingand understanding of the specification. The present invention includesall such equivalent alterations and modifications, and is limited onlyby the scope of the appended claims.

1. A valve actuator, comprising: a lower actuator housing having a boreextending therethrough; an actuator cylinder housing having acounterbore extending therein, said actuator cylinder housing secured insealing engagement to a first end of said lower actuator housing; alower actuator plate having bore extending therethrough, said loweractuator plate secured to a second end of said lower actuator housing; ahelix sleeve secured within said lower actuator housing bore and sealedtherein, said helix sleeve having a plurality of helical slots formed inthe wall of said helix sleeve, said helix sleeve including a reduceddiameter bore on one end; said actuator cylinder housing including abore axially coincident with said counterbore and formed on the end ofsaid actuator cylinder housing opposite to said lower actuator housing;an actuator drive shaft, said actuator drive shaft extending betweensaid actuator cylinder housing bore and said reduced diameter bore ofsaid helix sleeve and sealed within said bores and axially restrainedtherebetween; an actuator piston sleeve sealingly disposed in theannulus between said actuator drive shaft and said counterbore of saidactuator cylinder housing, said actuator piston sleeve axially moveablewithin said counterbore of said actuator cylinder housing in response tohydraulic pressure; said actuator piston sleeve having a reduceddiameter portion extending into the annulus between said actuator driveshaft and said helix sleeve, said reduced diameter portion of saidactuator piston sleeve sealing on said actuator drive shaft, saidreduced diameter portion of said actuator piston sleeve having aplurality of axially disposed slots formed therein; and, a firstactuation means secured to said reduced diameter portion of saidactuator piston sleeve and engaging said helical slots in said helixsleeve and a second actuation means secured to said actuator drive shaftand engaging said axially disposed slots in said reduced diameterportion of said actuator piston sleeve whereby reciprocation of saidactuator piston sleeve causes rotation of said actuator drive shaft. 2.A valve actuator, according to claim 1, wherein: said helix sleeve isaxially restrained between said actuator cylinder housing and said loweractuator plate.
 3. A valve actuator, according to claim 2, wherein: saidhelix sleeve is rotationally restrained by first securing meansextending between said helix sleeve and said lower actuator plate andsecond securing means extending between said helix sleeve and said loweractuator housing.
 4. A valve actuator, according to claim 3, wherein: afirst end of said actuator drive shaft seals within said bore of saidactuator cylinder housing and a second end of said actuator drive shaftseals within said reduced diameter bore of said helix sleeve.
 5. A valveactuator, according to claim 4, wherein: said first end of said actuatordrive shaft extends beyond said bore of said actuator cylinder housing;and, said first end of said actuator drive shaft has indicator meansformed thereon to indicate the rotational position of said actuatordrive shaft.
 6. A valve actuator, according to claim 5, wherein: saidsecond end of said actuator drive shaft extends beyond said reduceddiameter bore of said helix sleeve and through said bore of said loweractuator plate; and, said second end of said actuator drive shaftincludes an engaging means formed thereon for engaging a valve closureadapter which engages a stem of a valve to be operated by said actuator.7. A valve actuator, according to claim 6, wherein: said first andsecond actuation means are a plurality of rollers.
 8. A valve actuator,according to claim 7, wherein: said first and second securing meansrotationally restraining said helix sleeve are a plurality ofanti-rotation pins.
 9. A valve actuator, according to claim 8, wherein:said engaging means formed on said second end of said actuator driveshaft is a spline.
 10. A valve actuator, according to claim 1, wherein:said plurality of helical slots formed in the wall of said helix sleevehave a constant helix angle.
 11. A valve actuator, according to claim 1,wherein: said plurality of helical slots formed in the wall of saidhelix sleeve have a variable helix angle.
 12. A hydraulic control systemfor a valve actuator, comprising: first and second control valves, saidfirst and second control valves controlling operation of a valveactuator; said first and second control valves including inlet andoutlet ports fluidly connected, said inlet ports of said first andsecond control valves connected to a fluid pressure source, said firstand second control valves including a vent port and a manually operatedflow control member biased to a closed position preventing fluid flowbetween said inlet and outlet ports and allowing fluid flow between saidoutlet and vent ports; first through fourth pilot operated valvescontaining inlet and outlet ports fluidly connected, fluid flow betweensaid inlet and outlet ports controlled by a pilot pressure port operatedflow control member, said flow control member biased to a closedposition; said pilot pressure port of said first pilot operated valveconnected to said outlet port of said first control valve, said inletport of said first pilot operated valve connected to said fluid pressuresource, said outlet port connected to a first actuator fluid supplytank; said first actuator fluid supply tank fluidly connected to saidactuator whereby pressurized fluid from said first actuator fluid supplytank urges said actuator to a valve closed position; said outlet port ofsaid first pilot operated valve connected to said inlet port of saidsecond pilot operated valve, said outlet port of said second pilotoperated valve connected to an exhaust orifice valve; said pilotpressure port of said third pilot operated valve connected to saidoutlet port of said second control valve, said inlet port of said thirdpilot operated valve connected to said fluid pressure source, saidoutlet port connected to a second actuator fluid supply tank; saidsecond actuator fluid supply tank fluidly connected to said actuatorwhereby pressurized fluid from said second actuator fluid supply tankurges said actuator to a valve open position; said outlet port of saidthird pilot operated valve connected to said inlet port of said fourthpilot operated valve, said outlet port of said fourth pilot operatedvalve connected to said exhaust orifice valve; said first and secondactuator fluid supply tanks fluidly connected through a normally openvalve controlled by a pair of pilot ports, said pair of pilot portsconnected to said outlet ports of said control valves, respectively,and; said outlet port of said first pilot operated valve connected tosaid inlet port of said second pilot operated valve connected also tosaid pilot port of said third pilot operated valve, and said outlet portof said third pilot operated valve connected to said inlet port of saidfourth pilot operated valve connected also to said pilot port of saidsecond pilot operated valve.
 13. A hydraulic control system for a valveactuator, according to claim 12, wherein: said fluid pressure source isa gas pressurized pipeline through which said valve and valve actuatorcontrol flow.
 14. A hydraulic control system for a valve actuator,according to claim 13, wherein: said normally open valve connectedbetween said first and second actuator fluid supply tanks is an orificevalve.
 15. A hydraulic control system for a valve actuator, according toclaim 14, wherein: said orifice valve allowing equalization of pressurebetween said first and second actuator fluid supply tanks after saidfirst and second control valves are moved to said closed position; and,said equalized pressure between said first and second actuator fluidsupply tanks is bled to atmospheric pressure through said exhaustorifice valve.
 16. A hydraulic control system for a valve actuator,according to claim 15, wherein: said pressurized fluid supplied by saidfluid pressure source is a gas.
 17. A hydraulic control system for avalve actuator, according to claim 16, wherein: said pressurized fluidsupplied by said first and second actuator fluid supply tanks to saidactuator is oil; and, said oil being pressurized by said gas from saidfluid pressure source.
 18. A hydraulic control system for a valveactuator, according to claim 17, wherein: each of said first and secondfluid actuator tanks includes a manually operated pump, said pumpsoperable to supply pressurized fluid to said actuator to operate saidactuator between open and closed positions.
 19. A hydraulic controlsystem for a valve actuator, according to claim 18, wherein: said pumpsare disposed on said actuator tanks.
 20. A hydraulic control system fora valve actuator, according to claim 19, wherein: said pumps include ashuttle valve to allow operation of said pumps independently of saidfirst and second control valves.
 21. A hydraulic control system for avalve actuator, comprising: (a) first and second control circuits, saidfirst control circuit operating a valve actuator to close a valvesecured to said valve actuator and said second control circuit operatingsaid valve actuator to open said valve secured to said valve actuator;(b) a fluid pressure source; (c) an exhaust valve; (d) said valveclosing first control circuit including: (i) a control valve having amanually operated flow control member biased to a closed positionpreventing fluid flow between inlet and outlet ports and allowing fluidflow between said outlet and a vent port and said inlet port connectedto said fluid pressure source; (ii) first and second pilot operatedvalves containing a pilot pressure port operated flow control member,biased to a closed position, controlling fluid flow between inlet andoutlet ports; (iii) an actuator close fluid supply tank fluidlyconnected to said actuator whereby pressurized fluid from said actuatorclose fluid supply tank urges said actuator to a valve closed position;(e) said valve opening second control circuit including: (i) a controlvalve having a manually operated flow control member biased to a closedposition preventing fluid flow between inlet and outlet ports andallowing fluid flow between said outlet and a vent port and said inletport connected to said fluid pressure source; (ii) third and fourthpilot operated valves containing a pilot pressure port operated flowcontrol member, biased to a closed position, controlling fluid flowbetween inlet and outlet ports; (iii) an actuator open fluid supply tankfluidly connected to said actuator whereby pressurized fluid from saidactuator open fluid supply tank urges said actuator to a valve openposition; (f) a pilot operated normally open valve controlled by a pairof pilot ports allowing fluid communication between said actuator openfluid supply tank and said actuator close fluid supply tank, one of eachof said pair of pilot ports connected to said first and second controlcircuits; (g) said fluid pressure source connected to said inlet portsof said control valve and said first pilot operated valve of each ofsaid first and second control circuits; (h) each of said first andsecond fluid actuator tanks includes a manually operated pump, saidpumps operable to supply pressurized fluid to said actuator to operatesaid actuator between open and closed positions; said pumps include ashuttle valve to allow operation of said pumps independently of saidfirst and second control circuits; wherein: (i) operation of said firstcontrol circuit control valve to an open position; (i) directs fluidpressure to said pilot operated normally open valve to equalize pressurebetween said actuator open fluid supply tank and said actuator closefluid supply tank; (ii) directs fluid pressure from said outlet port ofsaid first control circuit control valve to said pilot port of saidfirst pilot operated valve of said valve closing first control circuitto operate said first pilot operated valve and allow fluid pressure topressurize said actuator close fluid supply tank and supply pressurizedfluid to said actuator to close said valve; and, (iii) directs fluidpressure from said outlet port of said first pilot operated valve ofsaid first control circuit to said pilot port of said fourth pilotoperated valve of said valve opening second control circuit to operatesaid fourth pilot operated valve and vent pressure from said actuatoropen fluid supply tank through said exhaust orifice valve; (j) operationof said second control circuit control valve to an open position; (i)directs fluid pressure to said pilot operated normally open valve toequalize pressure between said actuator open fluid supply tank and saidactuator close fluid supply tank; (ii) directs fluid pressure from saidoutlet port of said second control circuit control valve to said pilotport of said third pilot operated valve of said valve opening secondcontrol circuit to operate said third pilot operated valve and allowfluid pressure to pressurize said actuator open fluid supply tank andsupply pressurized fluid to said actuator to open said valve; (iii)directs fluid pressure from said outlet port of said third pilotoperated valve of said second control circuit to said pilot port of saidsecond pilot operated valve of said valve closing first control circuitto operate said second pilot operated valve and vent pressure from saidactuator close fluid supply tank through said exhaust orifice valve; (k)operation of said manually operated pump on said actuator close fluidsupply tank; (i) directs fluid pressure to close said actuator; and, (l)operation of said manually operated pump on said actuator open fluidsupply tank; (i) directs fluid pressure to open said actuator.
 22. Ahydraulic control system for a valve actuator, according to claim 21,wherein: said orifice valve allowing equalization of pressure betweensaid first and second actuator fluid supply tanks after said first andsecond control valves are moved to said closed position; and, saidequalized pressure between said first and second actuator fluid supplytanks is bled to atmospheric pressure through said exhaust orificevalve.
 23. A hydraulic control system for a valve actuator, according toclaim 22, wherein: said pressurized fluid supplied by said fluidpressure source is a gas.
 24. A hydraulic control system for a valveactuator, according to claim 23, wherein: said pressurized fluidsupplied by said first and second actuator fluid supply tanks to saidactuator is oil; and, said oil being pressurized by said gas from saidfluid pressure source.
 25. A system for controlling fluid flow through apipeline, comprising: (A) a valve, said valve installed in a pipeline toselectively control fluid flow through said pipeline; (B) an actuatorattached to said valve, said actuator operating said valve between openand closed positions; (C) a hydraulic control system, said hydrauliccontrol system controlling operation of said actuator; (D) said actuatorcomprising: (a) a lower actuator housing having a bore extendingtherethrough; (b) an actuator cylinder housing having a counterboreextending therein, said actuator cylinder housing secured in sealingengagement to a first end of said lower actuator housing; (c) a loweractuator plate having bore extending therethrough, said lower actuatorplate secured to a second end of said lower actuator housing; (d) ahelix sleeve secured within said lower actuator housing bore and sealedtherein, said helix sleeve having a plurality of helical slots formed inthe wall of said helix sleeve, said helix sleeve including a reduceddiameter bore on one end; (e) said actuator cylinder housing including abore axially coincident with said counterbore and formed on the end ofsaid actuator cylinder housing opposite to said lower actuator housing;(f) an actuator drive shaft, said actuator drive shaft extending betweensaid actuator cylinder housing bore and said reduced diameter bore ofsaid helix sleeve and sealed within said bores and axially restrainedtherebetween; (g) an actuator piston sleeve sealingly disposed in theannulus between said actuator drive shaft and said counterbore of saidactuator cylinder housing, said actuator piston sleeve axially moveablewithin said counterbore of said actuator cylinder housing in response tohydraulic pressure; (h) said actuator piston sleeve having a reduceddiameter portion extending into the annulus between said actuator driveshaft and said helix sleeve, said reduced diameter portion of saidactuator piston sleeve sealing on said actuator drive shaft, saidreduced diameter portion of said actuator piston sleeve having aplurality of axially disposed slots formed therein; and, (i) a firstactuation means secured to said reduced diameter portion of saidactuator piston sleeve and engaging said helical slots in said helixsleeve and a second actuation means secured to said actuator drive shaftand engaging said axially disposed slots in said reduced diameterportion of said actuator piston sleeve whereby reciprocation of saidactuator piston sleeve causes rotation of said actuator drive shaft; (E)said hydraulic control system comprising: (a) first and second controlvalves, said first and second control valves controlling operation of avalve actuator; (b) said first and second control valves including inletand outlet ports fluidly connected, said inlet ports of said first andsecond control valves connected to a fluid pressure source, said firstand second control valves including a vent port and a manually operatedflow control member biased to a closed position preventing fluid flowbetween said inlet and outlet ports and allowing fluid flow between saidoutlet and vent ports; (c) first through fourth pilot operated valvescontaining inlet and outlet ports fluidly connected, fluid flow betweensaid inlet and outlet ports controlled by a pilot pressure port operatedflow control member, said flow control member biased to a closedposition; (d) said pilot pressure port of said first pilot operatedvalve connected to said outlet port of said first control valve, saidinlet port of said first pilot operated valve connected to said fluidpressure source, said outlet port connected to a first actuator fluidsupply tank; (e) said first actuator fluid supply tank fluidly connectedto said actuator whereby pressurized fluid from said first actuatorfluid supply tank urges said actuator to a valve closed position; (f)said outlet port of said first pilot operated valve connected to saidinlet port of said second pilot operated valve, said outlet port of saidsecond pilot operated valve connected to an exhaust orifice valve; (g)said pilot pressure port of said third pilot operated valve connected tosaid outlet port of said second control valve, said inlet port of saidthird pilot operated valve connected to said fluid pressure source, saidoutlet port connected to a second actuator fluid supply tank; (h) saidsecond actuator fluid supply tank fluidly connected to said actuatorwhereby pressurized fluid from said second actuator fluid supply tankurges said actuator to a valve open position; (i) said outlet port ofsaid third pilot operated valve connected to said inlet port of saidfourth pilot operated valve, said outlet port of said fourth pilotoperated valve connected to said exhaust orifice valve; (j) said firstand second actuator fluid supply tanks fluidly connected through anormally open valve controlled by a pair of pilot ports, said pair ofpilot ports connected to said outlet ports of said control valves,respectively, and; (k) said outlet port of said first pilot operatedvalve connected to said inlet port of said second pilot operated valveconnected also to said pilot port of said third pilot operated valve,and said outlet port of said third pilot operated valve connected tosaid inlet port of said fourth pilot operated valve connected also tosaid pilot port of said second pilot operated valve, and; (l) each ofsaid first and second fluid actuator tanks includes a manually operatedpump, said pumps operable to supply pressurized fluid to said actuatorto operate said actuator between open and closed positions.
 26. A systemfor controlling fluid flow through a pipeline, according to claim 25,wherein: said helix sleeve is axially restrained between said actuatorcylinder housing and said lower actuator plate; said helix sleeve isrotationally restrained by first securing means extending between saidhelix sleeve and said lower actuator plate and second securing meansextending between said helix sleeve and said lower actuator housing;and, said fluid pressure source is a pressurized pipeline through whichsaid valve and valve actuator control flow.
 27. A system for controllingfluid flow through a pipeline, according to claim 26, wherein: a firstend of said actuator drive shaft seals within said bore of said actuatorcylinder housing and a second end of said actuator drive shaft sealswithin said reduced diameter bore of said helix sleeve; and, saidnormally open valve connected between said first and second actuatorfluid supply tanks is an orifice valve allowing equalization of pressurebetween said first and second actuator fluid supply tanks after saidfirst and second control valves are moved to said closed position; saidequalized pressure between said first and second actuator fluid supplytanks is bled to atmospheric pressure through said exhaust orificevalve; and, said pumps are disposed on said actuator tanks.
 28. A systemfor controlling fluid flow through a pipeline, according to claim 27,wherein: said second end of said actuator drive shaft extends beyondsaid reduced diameter bore of said helix sleeve and through said bore ofsaid lower actuator plate; said second end of said actuator drive shaftincludes an engaging means formed thereon for engaging a valve closureadapter which engages a stem of a valve to be operated by said actuator;said pressurized fluid supplied by said fluid pressure source is a gas;and, said pumps include a shuttle valve to allow operation of said pumpsindependently of said first and second control valves.
 29. A system forcontrolling fluid flow through a pipeline, according to claim 28,wherein: said first and second actuation means are a plurality ofrollers; said pressurized fluid supplied by said first and secondactuator fluid supply tanks to said actuator is oil; and, said oil beingpressurized by said gas from said fluid pressure source.
 30. A systemfor controlling fluid flow through a pipeline, according to claim 29,wherein: said first and second securing means rotationally restrainingsaid helix sleeve are a plurality of anti-rotation pins.
 31. A systemfor controlling fluid flow through a pipeline, according to claim 30,wherein: said engaging means formed on said second end of said actuatordrive shaft is a spline.
 32. A system for controlling fluid flow througha pipeline, according to claim 31, wherein: said plurality of helicalslots formed in the wall of said helix sleeve have a constant helixangle.
 33. A system for controlling fluid flow through a pipeline,according to claim 32, wherein: said plurality of helical slots formedin the wall of said helix sleeve have a variable helix angle.